This is a pilot project, initiated by GCRC nurses, to evaluate the use of prior topical heat on the success of IV catheter insertion to obtain sequential blood samples. The patients will be randomized into one of two groups to receive heat for 15 min. prior to IV insertion on day one of their 2 day admission. The other day, the IV will be inserted w/out the use of heat application. One nurse will insert all the IV catheters. The endpoint measure of the study will be the success rate in obtaining sequential blood samples.